The present invention is related to methods and apparatus for manufacturing dynamo-electric machines such as electric motors, generators, and similar apparatus. More specifically, the present invention relates to improved solutions for rapidly winding coils of wire on different sized cores of dynamo-electric machine using a mechanical winding machine.
Electric motors generally include two main components, a fixed portion and a rotating portion or xe2x80x9ccore.xe2x80x9d Often, the fixed portion is referred to as a xe2x80x9cstator,xe2x80x9d while the rotating core portion is often referred to as the xe2x80x9carmature.xe2x80x9d In these cases, the core typically includes a xe2x80x9crotorxe2x80x9d that rotates inside the stator. The rotating core may be an armature that is typically formed from a stack of laminated pieces of iron or steel and has a series of slots spaced around its circumference onto which wire is wound. A commutator may be attached to the rotor that provides an electrical connection to the armature. The rotor and the commutator are mounted in an axially spaced relation on a common shaft.
The commutator is formed from a series of circumferentially spaced conductive bars that each may include a connection point such as a xe2x80x9ctangxe2x80x9d to which the starting and ending leads of the wound coils are physically and electrically connected. While tangs are a commonly available type of connection point, persons skilled in the art will appreciate that other types of connections are also available. For example, instead of a tang, a channel or slot within a solid commutator bar may be used in which wire leads are inserted into the channel and the channel is then sealed around the wire. In either case, electricity supplied to the wire induces a current which interacts with a magnetic field produced in the stator to create torque that causes the motor to rotate.
There are numerous known machines that are capable of winding wire onto the slotted lamination stack. These winding machines have at least onexe2x80x94and often twoxe2x80x94wire applying devices known as xe2x80x9cflyersxe2x80x9d that rotate about an axis normal to that of the lamination stack. The flyers draw wire from a source and wind it around the slots to produce a wound coil having a desired number of turns. When a coil (or set of coils in the case of a double flyer machine) is completely wound, the flyers stop and the wire leads are brought next to the tangs or other connection points on the commutator to which they will be attached. The core is then rotationally indexed to present the tangs (or other connection points) to the wire hooking devices, and the flyer wraps wire around them. Rotational indexing also brings the next set of slots on the lamination stack into position to receive wire from the flyers.
Various examples of wire winding machines are described in, for example, Anderson U.S. Pat. No. 3,911,563, and in Lombardi et al. U.S. Pat. Nos. 5,127,594 and 5,257,745, all of which are commonly assigned with the present application. Each of the above identified patents are hereby incorporated by reference.
While such winders may be very effective for properly winding wire on the lamination stack slots, difficulties may arise when it is desired to wind wire around a core that does not have the same dimensions as the previously wound core. Currently available winding machines often require the center of each lamination stack to be aligned with a fixed axis on the machine. Moreover, two lamination stacks may have different centers even if they utilize a common sized shaft because, for example, the size of the lamination stack can also vary.
Additional difficulties also occur due to the multiple times a core is handled prior to winding. For example, one device may be used to form the core. This process includes selecting the proper number of laminations, stacking them on a rotor shaft, and fixing them in place. Then, a commutator must be added to complete the core. The completed core is then transferred to the winding machine, often with a known first index position (i.e., the first slot in the lamination stack to be wound). Problems may occur, however, during the transfer from the load/unload device to the gripper that holds the core in place during winding and that first index position may be lost. This causes a delay in the manufacturing process and may even require human intervention to insure that the core is properly indexed prior to winding.
Even if the first index position is not lost, known winding systems may be inherently slower than necessary due to other limitations. For example, in known winding systems, the winder must wait a given amount of time after a core is loaded for the load/unload device to move out of the way. This waiting time is directly proportional to the distance the load/unload device must travel to get out of the way. An additional delay is also inherent in that the winder must pause and wait while the loader/unloader travels that same distance prior to removing the wound core from the winder.
Conventional winding systems also typically are inherently inefficient as the winding flyers are idle for a large portion of each operational cycle. This is due to the way in which the cores are loaded and unloaded into the winding area. In known systems, a load/unload unit is utilized to remove wound cores and to place unwound cores into the winding area. Prior to and subsequent to each load/unload operation, the winding devices (including the flyers and winding guides) must be moved out of the way so that the load/unload unit may move inside the winding area to manipulate the cores. Due to the size of the typical load/unload unit, the time required for moving the winding systems out of and into position is relatively significant. The system cannot be winding while the winding systems are moving, resulting in inefficiency.
Further problems with conventional winding systems are the inherent problems in processing sequential cores which are different sizes. Each core must be aligned such that its center is co-located with the center of the flyers. The load/unload unit is often used to perform the alignment function as well. Unfortunately, this results in the load/unload unit being a substantially complex piece of equipment that requires a variable drive to accommodate different sized cores.
Additional problems also often occur in configuring automated winding systems. These problems are related to the fact that the systems, which typically include multiple hydraulic and/or air pressure lines, must be calibrated to run at specific operational pressures. Typical installations, however, often are configured such that the pressure controls, which are needed very infrequently after the initial baseline levels are set, are located in a hidden location such as underneath the operational console. While this may be convenient for normal operation, as well as being aesthetically pleasing, the conventional location of these controls often makes the initial setup very difficult, especially for a single operator. The operator simply cannot easily reach and adjust the controls while simultaneously observing the impact of those changes, due to the location of those controls.
In view of the foregoing, it is an object of this invention to provide methods and apparatus for transferring cores from a load/unload apparatus to a winding apparatus while retaining alignment of the lamination stack slots.
It also is an object of this invention to provide methods and apparatus for winding core coils in which the winding device is operational at an increased level of efficiency.
It is a further object of the present invention to provide methods and apparatus for simplifying sequential processing of different sized cores.
It is a still further object of the present invention to provide methods and apparatus for enabling an operator to adjust the initial pressure and other settings on the winding system while simultaneously being able to observe the impact of those adjustments.
These and other objects of the invention are accomplished in accordance with the principles of the invention by providing a novel transfer mechanism that minimizes the number of transfers of the core prior to winding. This significantly increases the likelihood that the indexing of the core will not be lost when the core is loaded into the winder, thereby enabling a more rapid winding process. An assembled, but unwound, core is grasped by a gripper of a load/unload device and oriented at a first index position. That position insures that a slot in the lamination stack will be in alignment with the winder when the core is placed into the winder. The core is then directly transferred to the holding gripper of the winder, while the first index position is maintained.
Another aspect of the present invention is related to the increase in efficiency of the winding system. This is related to the fact that the winding flyers are operational for a higher percentage of time than in conventional systems. The improvements in efficiency are obtained by increasing the capability of the equipment in the winding area and offloading functionality from the load/unload unit. In particular, the load/unload unit is limited to moving cores to and from a specific location that is outside of the winding area. Instead, the holding unit, which is located in the winding area, is provided with longitudinal movement capability and is tasked with the function of aligning the core with respect to the winders and winding guides, a task that was previously assigned to the load/unload unit. This provides multiple advantages.
One advantage results from the fact that the holding unit is much smaller than the load/unload unit, so that the winding systems do not have to be moved as far out of the way for load/unload operations. The less distance required for travel of the winding systems, the more time they may spend winding cores and the greater overall system efficiency. In addition, removing the alignment feature from the load/unload unit enables that unit to be significantly simpler because of the elimination of a variable drive. The present invention instead utilizes a fixed drive that may be implemented to simply move the load/unload unit from one fixed location to the next.
Further advantages of the present invention are obtained by the addition of longitudinal movement to the holding unit. In particular, because the holding unit and the load/unload unit are each moving toward the transfer point at the same time, they will necessarily meet at that point faster than in conventional systems. Accordingly, the transfer will occur sooner than in conventional systems and the alignment of the unwound core will also be accomplished faster. In this manner, the waiting time between each winding process is further reduced and the overall efficiency of the winding systems is increased.
Other features of the present invention are provided that increase the ease with which the system may be initially configured for normal operation. This process typically requires fine-tune adjustments of various pressure settings to insure that automated operation occurs smoothly. The present invention accomplishes this by relocating the pressure controls so that they are accessible to the operator while the operator is observing the operation of the system. This requires the controls, which are typically located in a hidden or isolated location because they are seldom used after the initial settings are made, to be within the reach of the operator during observation of the system, and preferably located in the back of the system (i.e., opposite to where the cores are loaded and unloaded).